The long term objective is a practical clinical Raman instrument with a fiberoptic probe, for use with a bronchoscope, for characterizing bronchial tissue with respect to precancerous conditions. The system will be especially effective with a new generation of bronchoscopes that have their screening efficacy enhanced by use of auto-fluorescence or other spectroscopic imaging methods. [unreadable] [unreadable] Since lung cancer is the second most common cancer in humans, is the most common cause of cancer deaths in the world, and has a very low (14%) five year survival rate, an instrument that can be easily utilized with normal bronchoscopy procedures will add clinical medical value by enabling real time examination of suspicious sights, with enhanced sensitivity relative to white light bronchoscopy alone. This will enable greater yield of "positives" from those sites that are chosen for biopsy. [unreadable] [unreadable] The Specific Aims for Phase I are: (1) The acquisition of Raman spectra at an excitation wavelength of 830 nm from in-vitro samples of normal, dysplastic and cancerous lung tissue, using free-space propagating beams. (2) The production and testing of a small-diameter, filtered, fiberoptic Raman probe, suitable for insertion through the biopsy channel of a bronchoscope. (3) The development of real-time data analysis algorithms which can indicate the state of the observed tissue on the basis of characteristic signatures described in the literature. Basic Raman data will be obtained on in vitro bronchial tissue to assist probe design and algorithm development. Probes will be designed, fabricated and used with a Raman prototype instrument on in vitro bronchial tissue samples to compare with modeling calculations and demonstrate feasibility of a real-time in vivo instrument for use in conjunction with a bronchoscope in clinical examinations. [unreadable] [unreadable]